1. Field of the Invention
The present invention relates to a backlight inverter system. More particularly, the present invention relates to a backlight inverter system which is capable of stably starting a backlight when power is supplied to the system for the first time and for driving a backlight lamp in a normal condition, and a control method for starting the same.
2. Description of the Related Art
Compact and light LCD (Liquid Crystal Display) devices have been increasingly employed as viewfinder displays. Since the LCD works on the principle of receiving light rather than emitting light, a backlight of high transmissivity attached to a rear surface of a liquid crystal plate of the LCD renders image information displayed on the LCD clearer with a uniform luminance. The backlight typically uses a backlight lamp to emit light, which is fabricated by downsizing a general fluorescent light lamp into a suitable size for the backlight. Even with a small size, the backlight lamp has an efficiency that rivals that of the fluorescent light lamp.
The backlight lamp contains therein a positive and a negative (i.e., +, −) discharge electrode, a mercurial vapor, an argon gas, and a fluorescent membrane which is coated on the outer surface of the lamp. When a voltage is applied to the discharge electrode, the inner gases collide with one another and heat the fluorescent membrane, thereby generating light. In order to start the backlight lamp with power supplied to the LCD, a voltage higher than that of a normal condition, and sufficient to activate the inside of the lamp, must be applied.
In order to normally start a backlight inverter system at a low temperature, a voltage higher than that typically applied at a high temperature is required. If a start-up voltage suitable for a low temperature condition is applied at a high temperature, an automatic shut-down function has to be performed to prevent damage to the inside of the backlight. However, the shut-down function may not always be achieved, which can result in damage to the system. In order to solve this problem, some attempted solutions adopt a passive and dependent method that apply an intermediate voltage value to prevent problems at both high and low temperatures.
Accordingly, a need exists for a method and system that overcomes the deficiencies of prior attempted solutions by stably starting a backlight inverter system according to the ambient temperature without harm or damage to the system.